Re: [mux@FreeBSD.org: Re: Anyone interested in improving postgresql scaling?]

On Thu, Apr 12, 2007 at 12:57:32PM -0400, Bruce Momjian wrote:
> Tom Lane wrote:
> > Kris Kennaway <kris(at)obsecurity(dot)org> writes:
> > > On Wed, Apr 11, 2007 at 01:03:50AM -0400, Tom Lane wrote:
> > >> Well, the thing is, we've pretty much had it handed to us that
> > >> current-command indicators that aren't up to date are not very useful.
> > >> So rate-limited updates strike me as a useless compromise.
> >
> > > I don't get your argument - ps auxww is never going to be 100%
> > > up-to-date because during the time the command is running the status
> > > may change.
> >
> > Of course. But we have already done the update-once-every-half-second
> > bit --- that was how pg_stat_activity used to work --- and our users
> > made clear that it's not good enough. So I don't see us expending
> > significant effort to convert the setproctitle code path to that
> > approach. The clear way of the future for expensive-setproctitle
> > platforms is just to turn it off entirely and rely on the new
> > pg_stat_activity implementation.
>
> 8.3 will modify less memory to update the process title than happened in
> the past --- perhaps that will reduce the overhead, but I doubt it. You
> can test CVS HEAD to check it.

Yeah, this is not relevant for BSD, it uses a syscall to set it (which
is why it has high overhead) instead of just modifying user memory.

Kris